Electro-static discharge (ESD) is an objective natural phenomenon, which may be caused in such ways as contact, friction, and the like. ESD is characterized by high voltage, low power, small current, and short action time.
With the ever increasing integration of electronic elements, hazards caused by ESD on electronic elements in the integrated circuits arouse increasing focus on product design and manufacturing.
In digital circuits, if high ESD occurs at a power source of a digital circuit, it can easily cause a relatively low pulse peak for the power source signal of the digital circuit against the power source ground. As a result, the digital circuit may not normally work, or even may be damaged.